Method for forming a multiple sectional ring

ABSTRACT

A METHOD AND APPARATUS FOR FORMING A RING STRUCTURE COMPRISED OF A MULTIPLE NUMBER OF ELEMENTS SUBSTANTIALLY FORMING THE RING, WHICH SECTIONS ARE UTILIZED IN CATHODE RAY GUNS TO PROVIDE THE ELECTRICAL CIRCUIT FOR ENERGIZING THE CATHODE FILAMENTS OF THE ELECTRON GUN. FOUR SEPARATE SECTIONS FORM THE RING. THE METHOD AND APPARATUS FOR FORMING THE ARRANGEMENT IS TO PROVIDE A SINGLE DAMP MEMBER HAVING THE THICKNESS OF THE ORDER OF 5 MILS AND MOUNTING THE MEMBER UPON A JAKE TO FORM A SUBSTANTIALLY CIRCULAR SHAPED CONFIGURATION. THE MEMBER IS THEN POSITIONED IN CLOSE PROXIMITY TO THE ELECTRON GUN STRUCTURE ADJACENT THE ELEMENTS TO WHICH IT IS BEING MECHANICALLY CONNECTED. THE RING SHAPED MEMBER IS THEN WELDED TO THE SUPPORTING STRUCTURES AND, AFTER WELDMENT, IS POSITIONED IN A RING CUTTER ASSEMBY WHICH CUTS THE SUBSTANTIALLY RING SHAPED MEMBER AT THREE POINTS LOCATED APPROXIMATELY 120* APART TO THEREBY FORM FOUR SEPARATE ELEMENTS WHICH ARE THEN UTILIZED FOR ELECTRICAL CONNECTION TO FILAMENT LEADS OF A PLURALITY OF CATHODE HEATERS MOUNTED WITHIN THE ELECTRON GUN STRUCTURE. THIS TECHINQUE REPLACES THE CONVENTIONAL TECHNIQUE IN WHICH SIX SEPARATE ELEMENTS ARE UTILIZED TO FORM THE FILAMENT RING.

Feb. 16, 197 1 D. MINUTILLO 3,562,898

METHOD FOR FORMING A MULTIPLE SECTIONAL RING Filed May 8, 1969 3Sheets-Sheet 1 7 /z. Z I/, m

547;? yarn/4; 515:4; 'ieaffarrfv Feb. 16, 1971 Filed May 8, 1969 L. D.MINUTILLO 3,562,898

METHOD FOR FORMING A MULTIPLE SECTIONAL RING 3 Sheets-Sheet 2 Feb. 16,1971 MINUTILLO- 3,562,898

METHOD FOR FORMING 'A MULTIPLE SECTIONAL RING Filed May 8, 1969 I 5Sheets-Sheet 5' I 5 I, I 975 f\ O O 7%6 I l l l 72' 734. 75

United States Patent 3,562,898 METHOD FOR FORMING A MULTIPLE SECTIONALRING Leonard D. Minutillo, Parlin, N.J., assignor to GriflithsElectronics, Inc., Linden, N.J., a corporation of New Jersey Filed May8, 1969, Ser. No. 822,961 Int. Cl. 323k 31/02 U.S. Cl. 29471.3 3 ClaimsABSTRACT OF THE DISCLOSURE A method and apparatus for forming a ringstructure comprised of a multiple number of elements substantiallyforming the ring, which sections are utilized in cathode ray guns toprovide the electrical circuit for energizing the cathode filaments ofthe electron gun, Four separate sections form the ring. The method andapparatus for forming the arrangement is to provide a single damp memberhaving the thickness of the order of 5 mils and mounting the member upona jake to form a substantially circular shaped configuration. The memberis then positioned in close proximity to the electron gun structureadjacent the elements to which it is being mechanically connected. Thering shaped member is then welded to the supporting structures and,after weldment, is positioned in a ring cutter assembly which cuts thesubstantially ring shaped member at three points located approximately120 apart to thereby form four separate elements which are then utilizedfor electrical connection to filament leads of a plurality of cathodeheaters mounted within the electron gun structure. This techniquereplaces the conventional technique in which six separate elements areutilized to form the filament ring.

The present invention relates to electron tube fabrication and moreparticularly to a novel method and apparatus for fabricating cathode raytube electron guns especially of the type employed in color TV tubeswherein the six separate elements heretofore utilized to form thefilament ring are replaced by a single element which is then welded andcut at predetermined locations to form the filament ring.

In order to mass produce electron tubes of the type having amultiplicity of components it becomes necessary to both automate as manyoperations in electron tube fabrication as is possible, as well asstriving to reduce the number of total operations required in thefabrication of electron tubes.

As one example, in the mass production of electron gun assembliesutilized in color TV receiver tubes, the number of components comprisingthe electron gun is large and hence the number of fabrication steps isquite large, necessitating automation and a reduction in the number offabricating steps to the greatest practical extent.

Electron gun structures utilized in color TV receiver tubes of theshadow-mask type are each comprised of three separate electron gunsarranged substantially at 120 intervals about a central axis in order toproduce the three separate electron beams which are scanned across thetube shadow-mask to pass through the openings in the shadow-mask and toimpinge upon the associated colors of the phosphor dot pattern andthereby reproduce the original color image. The filaments of theindividual electron guns within the composite structure are connected inelectrical circuit by means of a filament ring comprised of a number ofseparate components sufiicient to electrically couple all of thefilament leads as well as to provide two tabs for electrical connectionto 3,562,898 Patented Feb. 16, 1971 the filament power supply.Conventional methods for fabricating the filament ring consisted ofproviding the total number of individual segments, positioning thesesegments relative to the filament leads, welding the components toassociated supporting structures and then welding these elements toassociated leads of the filaments. Components which serve to provide thefilament power are typically arranged in a ring-shaped fashion and arecommonly referred to as collectively forming the filament ringstructure. Due to the rather small size and fragile nature of thesecomponents, handling and welding becomes rather complex and tedious.

The present invention is characterized by providing novel apparatus forfabricating the filament ring structure in which only a single part isutilized to form the composite ring structure, which single member isappropriately welded to the supporting structure and then simultaneouslycut in a plurality of locations and by a single cutting operation toform the separate segments or sections of the filament ring preparatoryto the welding of the separate sections to the cathode heater filamentleads.

The present invention is comprised of a heater ring fixture forreceiving and positioning, in arcuate form, a single stamped member. Thefixture which is formed of a metal having good conductive properties isplaced in a welding fixture so as to operate as a first electrode of thewelding apparatus. The remaining structure of the electron gun islightly force-fitted to one end of the fixture so as to be aligned withthe single stamped member. The welding unit includes a second weldingelectrode and means for positioning the second electrode relative topoints between the stamped member and the related supporting componentsof the electron gun structure and then producing each weld. Uponcompletion of the welding operation, the stamped member issimultaneously cut at predetermined intervals around its periphery toform the final filament heater ring which is then ready to be joined tothe individual filaments. This method and ap paratus thereby enables thefilament heater ring to be fabricated rapidly and accurately throughmass production techniques, wherein the operations are performedsubstantially automatically and the number of fabrication steps aresubstantially reduced.

It is therefore one object of the present invention to provide a novelmethod and apparatus for forming the heated ring assembly of electrongun structures in a rapid, reliable and substantially automatic fashion.

Another object of the present invention is to provide a novel fixtureand ring cutter and machine for forming a heater ring assembly whereinthe fixture is designed to hold a single stamping member, to operate asan electrode for the welding operation and wherein the ring cuttingmachine simultaneously cuts the stamping into three separate componentspreparatory to establishing the electrical circuit path for the heaterfilament leads such that the above fabrication steps are performedrapidly and accurately as compared with the conventional techniques.

These as well as other objects of the present invention will becomeapparent when reading the accompanying description and drawings inwhich:

FIG. 1 is a plan view showing the stamped part utilized with the methodand apparatus of the present invention.

FIGS. 2a and 2b are side and end views respectively of the heater ringfixture utilized for mounting the stamping shown in FIG. 1.

FIGS. 3a and 3b are elevational and top views respectively, showin anelectron gun structure fabricated in accordance with the principles ofthe present invention FIG. 4 is a plan view showing a welding apparatuswhich may be utilized with the apparatus of the present invention.

FIGS. 51: and b are end views, respectively, showing the cuttingapparatus of the present invention.

FIGS. 6a, 6b and 6c show further details of the apparatus of FIGS. 5aand 5b, wherein FIG. 6a is a sectional vie-w taken along the lines A-Aof FIG. 6a and wherein FIG. 6c is a sectional view taken along the linesB-B' of FIG. 6a.

Referring now to the drawings, FIG. 1 shows a plan view of a stampingutilized with the method and apparatus of the present invention in whichstamping 10 is a fiat metallic member which may preferably be stainlesssteel, whose planar dimensions are preferably as shown in the figure andwhose thickness is of the order of 0.005 inch. As can clearly be seenfrom this figure, the stamped member is a substantially flat thinmetallic member and has a C-shape configuration comprised of a centralportion 11 and upwardly projecting arms 12 and 13 which form tabs forconnecting an electrical circuit thereto in a manner to be more fullydescribed.

FIG. 3a shows an elevational view of a portion of an electron gunassembly and FIG. 3b shows the top view of the electron gun assembly ofFIG. 3a which may be fabricated in accordance with the concepts of thepresent invention. The electron gun assembly is comprised of threeseparate electron gun portions 21-23 which are arranged at 120 intervalsabout a central axis designated by the point 24 in FIG. 312. Since allof the electron gun structures are substantially identical to oneanother, only one of these structures will be described herein forpurposes of simplicity. The electron gun 22 is comprised of a cathodemember 25 welded within a supporting cylinder 26. The cathode is heatedto a temperature sufiicient to cause the cathode to emit electrons withthe electron emission toward the face of the cathode ray tube beingcontrolled by a control grid 27. The cathode 25 is heated by a filamentpositioned within the hollow interior 25a of cathode 25 and is a thinwire which heats the cathode to an elevated temperature level suflicientto cause the cathode to emit electrons. The filament is provided with apair of leads 128 extending out of the opening 25a of the cathode, whichleads are then electrically connected to a pair of conductive sections29 and 30. The filament leads of electron gun 21 are similarlyelectrically connected to conductive members 29 and 31, while thefilament leads of electron gun 23 are electrically connected toconductive members 30 and 32, respectively, to form a series circuitsimultaneously energizing all of the filaments of the three electronguns 21-23. The electrical circuit is established through a pair of tabsintegrally formed with and extending upwardly from conductive pieces 31and 32, which tabs are designated by the numerals 33 and 34,respectively.

The electron gun structure is further provided with three elongatedinsulating members 35-37 which mechanically support all components ofthe electron gun structure while electrically insulating all of theparts. These insulating members, such as, for example, member 35 areprovided with a pair of metallic support members 38 and 39 whose firstends are imbedded into the insulating member 35 and whose free ends arebent outwardly to form welding surfaces for the support of conductivemember 29. Insulating members 36 and 37 are likewise provided withsupports for respectively welding conductive segments 30, and 3132thereto. It can clearly be seen from a consideration of FIG. 3b that theconductive members 2932 form a circular or ring-shaped configuration andhence are referred to as the cathode heater ring assembly.

Heretofore the separate segments 2932 were individually cut to size andformed so as to have an arcuate shape, after *Which these separatesections were then welded to the associated supports. The presentinvention provides a method and apparatus for forming the cathode heaterring assembly from a single stamped member of the type shown in FIG. 1,which single member is then bent to form the circular configurationwelded to the aforementioned supports and then cut at the gaps 40, 41and 42 between the separate sections so as to automate the fabricationof the cathode heater ring assembly and to eliminate a number offabrication steps and thereby simplify the manufacture of electron gunstructures of the type shown in FIGS. 3a and 3b.

FIGS. 2a and 2b are top and side views, respectively, of a ring fixture15 utilized to form and weld the fiat stamped member 10 of FIG. 1 to theelectron gun structure.

The ring fixture 15 is formed of a conductive metallic material and iscomprised of a first cylindrical shaped member 16 having a centralopening 160. A second circular shaped member 17 formed of a conductivemetallic material has its left-hand end (relative to FIG. 2b) insertedinto the right-hand end of opening 16a. These members are rigidly joinedto one another by suitable fastening means (not shown) threadedlyengaging tapped apertures 18a18c and having their forward ends bearingagainst the surface of member 17 to rigidly secure member 17 withinmember 16.

Metallic member 17 is provided with a circular shaped flange 17a havingtwo slots 17b and 170.

The stamped member 10 (see also FIG. 1) is placed around the peripheryof member 17 near its right-hand end so that the tabs 12 and 13 passthrough slots 17b and 17c and extend into a groove 16b formed betweenflange 17a and a continuous shoulder 16c formed in member 16. A closedloop garter spring (shown only in sectional fashion in FIG. 2b) isfitted around groove 16b so as to bear upon tabs 12 and 13 and maintainthe stamped member 10 in the curved position about member 17 as shownbest in FIG. 2b. This fixture is then placed upon a welding apparatus50, shown in FIG. 4. The welding apparatus 50 is comprised of a motor 51or any other suitable driving means for the purpose of rotating a shaft52 mechanically coupled thereto. The opening 16a of fixture 15 is forcefitted upon the end of shaft 52 in the manner shown in FIG. 4. Theelectron gun structure 20 (minus the cathode heater ring) is forcefitted upon the right-hand end of fixture 15 so that its support members(see support members 38 and 39, for example, of FIG. 3b) embrace thestamped member 10 such that the support members make physical engagementwith the stamped member at spaced intervals around its surface. A pin 19fitted into an opening 17d in fixture member 17 further acts tocentrally locate and orient the electron gun structure 20 relative tofixture 15. The pin is positioned in the open space between the electrongun structures and is substantially aligned with the longitudinal axisof the gun structure as represented by the point 24 of FIG. 3b. Pin 19orients the location of the ring tabs with respect to each of theelectron gun barrels, i.e., the red, green or blue gun.

The fixture 15 is electrically coupled by any suitable means to anenergy source 53. The electrical coupling may be by means of a lead 54which may be electrically connected either to fixture 15 or shaft 52. Ifdesired, lead 54 may make sliding electrical connection with eithershaft 52 or fixture 15. An insulating coupled 55 may electricallyinsulate motor source 51 from fixture 15 while mechanically coupling theoutput of motor 51 to the fixture. The fixture 15 serves as oneelectrode of the welding apparatus. The other electrode is coupled bylead 56 to a second electrode 57 positioned along one radius of thefixture and having its tip immediately adjacent the outer periphery ofthe electron gun support members (such as support members 38 and 39, forexample).

The welding operation is performed in the following manner:

Motor means 51 is energized to rotate fixture 15 in order to positionthe points to be welded immediately beneath the tip of electrode 57. Forexample, considering FIG. 3b, the first weld may occur at point 58 forthe purpose of joining support 39 to segment 29. Obviously, the

starting point may occur anywhere around the periphery of the electrongun structure and point 58 is merely cited as being one exemplarystarting point. Motor means 51 is deenergized to hold this position andenergy source 53 is energized to provide a weld at point 58. Motor means51 is then energized rotating fixture 15 so as to locate point 59 (seeFIG. 3b) immediately adjacent the tip of electrode 57. Motor means 51 isthen deenergized and energy source 53 is energized to produce a weld atpoint 59. Before rotation of fixture 15, electrode 57 is retracted byeither mechanical or automatic means so as to move the electrode in thedirection shown by arrow 60 to provide sufiicient clearance for supportmember 36 upon rotation of fixture 15. Motor means 51 is then energizedto place point '61 immediately beneath the tip of electrode 57.Electrode 57 is then moved either by mechanical or manual means in thedirection shown by arrow 62 so as to have its tip immediately adjacentpoint 61. Energy source 53 is then energized to produce a weld at point61. The fixture 15 is repeatedly rotated and electrode 57 is furtherretracted when necessary to provide welds at the points 63, 64 and 65 soas to weld the stamped member at spaced intervals around its surface toassociated supports of the electron gun structure.

Upon completion of the welding operation, the electron gun structure maysimply be removed from fixture 15 and placed in a cutting assembly toform the separate segments 29, 30, 31 and 32 by means of a cuttingassembly shown in FIGS. 5a6c.

Cutting assembly 70 is comprised of a support or base member 71 whichmay be placed on any suitable support surface. A cutter base 72 ismounted upon the plate 71 by means of three stands off 73a-73c whosebottom ends are secured by fastening means 75 (only one of which isshown in FIG. 5b for purposes of simplicity), and whose top ends aresecured to cutter base 72 by fastening means 76a-76c, respectively.Cutter base 72 is provided with a central opening 72a surrounded by anupwardly extending flange portion 72b integrally formed with space 72. Acylindrical shaped mandrel 73 is positioned within opening 72a and hasits lower end 73a (of slightly smaller diameter) force fitted into acooperating opening 74a provided in mandrel locating block 75 secured tobase 72 by fastening means 76. Mandrel 74 is provided with a circulargroove 7417 near its upper end and with three slots 74c-74e arranged at120 intervals about the top end of the mandrel.

A ring shaped member 77 is secured to base 72 and is provided with anopening 77a which surrounds and is spaced from flange 721). Member 77 isprovided with a fiat circular shaped surface 77b for slidably supportinga cam ring 78 which may be rotated in opposing directions as shown bydouble headed arrow 79 by an operating mechanism to be more fullydescribed.

The operating mechanism is comprised of an air cylinder apparatus 79having a first end thereof secured to support member 71 by fasteningmeans 80. While not shown in detail for purposes of simplicity, itshould be understood that the air cylinder assembly 79 is provided witha hollow cylindrical shaped interior for reciprocally mounting andmoving a piston member mechanically coupled to a connecting rod 81. Theforward end of the connecting rod is provided with an eyelet 82 forreceiving a fastening member 83 which threadedly engages a tappedaperture 78a provided in cam ring provided in cam ring 78. In operationair pressure is introduced into the cylinder (by means not shown)causing connecting rod 81 to move toward the right (relative to FIG. 5a)to rotate cam ring 78 in a counterclockwise direction relative to FIG.5p. Removal of the air pressure and application of a vacuum oralternatively application of air pressure in the opposite surface of thepiston serves to move connecting rod 81 toward the left relative to FIG.5a causing the cam ring 78 to rotate in the clockwise direction relativeto FIG. 5a.

Cam ring 78 is provided with three elongated cam slots 79a-79c arrangedat substantially equally spaced intervals about the cam ring. Each ofthese slots receive a cam follower 8284 respectively, which are arrangedto slidably engage the peripheries of their associated slots. Since eachof the cam followers are substantially identical in configuration andfunction, only one will be described herein for purposes of simplicity.Considering FIG. 6b, the cam follower 84 slidably engaging slot iscomprised of a circular shaped roller member 83a mechanically coupled toa pin 83b extending into a suitable opening provided in member 77. Pin83b is secured within the opening in member 77 by means of a set screw85 fitted into a tapped aperture 770 so as to secure pin 83b to member77. Roller 83a is secured to pin 8312 so as to prevent any linear motionbetween the two parts, thereby preventing roller 83 from liftingupwardly and away from pin 83b. However, roller 83a is free to rotateabout pin 83b. Each of the blocks 77, 88 and 89 (see FIGS. 6a and 6c) isprovided with a pair of shoulders such as for example, the shoulders 77dand 77e arranged to slide within an elongated slot 90a provided within acover plate 90. Similar slots are provided for each of the members 88and 89. Circular cover plate 90 may be secured to cutter base 72 in anysuitable manner such as by elongated fastening means, for example, whichmay be positioned at spaced intervals between the slides 77, 88 and 89.The slide 77 is provided with a narrow elongated slot 77d fitted with acutter member 91 shown best in FIG. 6b. Three such cutter members 91-93are provided for each of the slides 77, 88 and 89, respectively. Eachcover plate is fitted with a slide cover such as, for example, the cover94 secured to the top of the slide 88 by fastening means 95. Slide 77,shown in FIG. 6a, has its slide cover removed and shows a portion of thecover plate 90 broken away to expose the shoulders 77d and 77s in theslide. However, the cover plate 96 and fastening means 97 are shown inFIG. 6a for slide 89. Each of the cutters are provided with a sharpforward edge arranged to pass through associated slots 74c, and 74d and74e provided in mandrel 74. In operation, the electron gun structure isplaced upon the mandrel 74 which is provided with two projections 98 and99 that are arranged to fit in the openings 100 and 101 shown in FIG. 3bwhich are defined by the ring sections and the supports to which theyare welded. This establishes orientation between the cutter blades andthe electron gun structure. Initially, the connecting rod 81 is in itsuppermost position (not shown) relative to FIG. 6a. Air pressure isintroduced to move the connecting rod 81 vertically downward relative toFIG. 6a to thereby move the cam ring 78 in the counterclockwisedirection. The cam followers 82-84 move inward along respective radii ofthe cutter to form the gaps 40, 41 and 42, shown best in FIG. 3b. Theair cylinder 79 is then operated to move the connecting rod 81vertically upward relative to FIG. 6a causing the cam rmg 78 to rotatein the clockwise direction and thereby remove the slides and theirassociated cutters outwardly along their respective radii. The electrongun structure may then be removed and transferred to the next locationwhereupon the heater filaments may be inserted within the cathodeopenings and these filament leads such as the filament leads 28 may thenbe welded or otherwise electrically connected to the associated ringsection such as, for example, sections 29 and 30, to establish a serieselectrical circuit to connect a power supply through tabs 12 and 13 toeach of the three filaments of the electron guns comprising thestructure.

It can be seen from the foregoing description that the present inventionprovides an automated means for simply and rapidly forming a cathodeheater ring assembly and electron gun structures in which the number offabrication steps are significantly reduced as compared withconventional techniques through the use of a single stamped member whichis formed in an arcuate manner upon a fixture positioned relative to theelectron gun structure welded at a plurality of locations and then cutinto a single cutting operation to form the cathode heater ringassembly.

Although there has been described a preferred embodiment of this novelinvention, many variations and modifications will now be apparent tothose skilled in the art. Therefore, this invention is to be limited,not by the specific disclosure herein, but only by the appending claims.

What is claimed is:

1. A method for forming a ring shaped structure comprised of separatesections welded to associated supports provided in a support structurecomprising the steps of:

(a) providing a flat C-shaped metallic member;

(b) positioning said member about a circular shaped fixture to impart acircular configuration to said member;

(0) releasably securing the arms of said member to said circular shapedfixture to cause said member to retain its circular configuration;

(d) fitting said structure upon said fixture with said supports engagingsaid member at points along its outer surface;

(e) welding said supports to said member at each of said points;

' upon a rotatable structure;

rotating said fixture to sequentially index each of said points for thewelding operation.

References Cited UNITED STATES PATENTS 7/1968 Dorota 29-25.16X 9/1969Lowery, Jr. et al. 29-25.16

JOHN F. CAMPBELL, Primary Examiner V. A DIPALMA, Assistant Examiner US.Cl. X.R. 2925.16, 475, 481

